AM79C981 datasheet(29/40 Pages) AMD

29 / 40 page

AMD

PRELIMINARY

1–99

Am79C981

SWITCHING CHARACTERISTICS (continued)

Notes:

1. Parameter not tested.

2. Uses switching test load.

3. DI pulses narrower than tPWODI (min) will be rejected; pulses wider than tPWODI (max) will turn internal DI carrier sense on.

4. DI pulses narrower than tPWKDI (min) will maintain internal DI carrier sense on; pulses wider than tPWKDI (max) will turn internal

DI carrier sense off.

5. CI pulses narrower than tPWOCI (min) will be rejected; pulses wider than tPWOCI (max) will turn internal CI carrier sense on.

6. CI pulses narrower than tPWKCI (min) will maintain internal CI carrier sense on; pulses wider than tPWKCI (max) will turn

internal CI carrier sense off.

7. RXD pulses narrower than tPWKRD (min) will maintain internal RXD carrier sense on; pulse wider than tPWKRD (max) will

turn internal RXD carrier sense off.

8. For the typical twisted pair load as shown in Figure 7, using a 100

Ω cable, an additional 28 mA (max) of IDD current is

required for each twisted pair port used. Less than 18% of the power associated with this additional current is dissipated

by the IMR+ chip; the remainder is dissipated externally in the twisted pair load and cable.

AM79C981 Datasheet(PDF) 29 Page - Advanced Micro Devices